package com.icbc.util;

//重写这个类，解决换行问题
public class BASE64Encoder {
	  private static char[] codec_table = { 'A', 'B', 'C', 'D', 'E', 'F', 'G',  
          'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',  
          'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',  
          'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',  
          'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6',  
          '7', '8', '9', '+', '/' };  

  public BASE64Encoder() {  

  }  

  public static String encode(byte[] a) {  
      int totalBits = a.length * 8;  
      int nn = totalBits % 6;  
      int curPos = 0;// process bits  
      StringBuffer toReturn = new StringBuffer();  
      while (curPos < totalBits) {  
          int bytePos = curPos / 8;  
          switch (curPos % 8) {  
          case 0:  
              toReturn.append(codec_table[(a[bytePos] & 0xfc) >> 2]);  
              break;  
          case 2:  

              toReturn.append(codec_table[(a[bytePos] & 0x3f)]);  
              break;  
          case 4:  
              if (bytePos == a.length - 1) {  
                  toReturn  
                          .append(codec_table[((a[bytePos] & 0x0f) << 2) & 0x3f]);  
              } else {  
                  int pos = (((a[bytePos] & 0x0f) << 2) | ((a[bytePos + 1] & 0xc0) >> 6)) & 0x3f;  
                  toReturn.append(codec_table[pos]);  
              }  
              break;  
          case 6:  
              if (bytePos == a.length - 1) {  
                  toReturn  
                          .append(codec_table[((a[bytePos] & 0x03) << 4) & 0x3f]);  
              } else {  
                  int pos = (((a[bytePos] & 0x03) << 4) | ((a[bytePos + 1] & 0xf0) >> 4)) & 0x3f;  
                  toReturn.append(codec_table[pos]);  
              }  
              break;  
          default:  
              //never hanppen  
              break;  
          }  
          curPos+=6;  
      }  
      if(nn==2)  
      {  
          toReturn.append("==");  
      }  
      else if(nn==4)  
      {  
          toReturn.append("=");  
      }  
      return toReturn.toString();  

  }  
}  